Highly filled polymer compositions are used extensively in commercial applications, such as flame retardant (FR) and halogen-free flame retardant (HFFR) applications; sound management applications; flooring applications; wire and cable applications; roofing membrane applications; wall covering applications; magnetic sheet/strip applications; carpet backing; containers and automotive applications. Likewise, such highly filled polymer compositions can be used as master batch with filler highly loaded.
High melt flow rate polyolefins, such as polypropylene and polyethylene homo- and copolymers, are used in this field with the limitation of low levels of filler incorporated, poor processability, and poor mechanical properties. The homogeneity of such very high melt flow rate polyolefins incorporated with high amount of filler is generally low.
U.S. Pat. No. 7,737,206 to Trazollah Ouhadi disclosed a composition consisting essentially of a propylene copolymer, a filler, a homopolypropylene and a synthetic or natural rubber. U.S. Pat. No. 7,335,696 to Selim Yalvac et. al. disclosed a composition comprising ethylene/alpha-olefin copolymer and fillers loaded in an amount of greater than 40 percent by weight of the polymer composition.
There is, therefore, a need for a novel polymer composition suitable for the fabrication of finished articles and/or as a pigment/filler masterbatch. It would be desirable to utilize very high levels of filler for these applications, typically at least 15 wt %, preferably at least 30 wt %, more preferably at least 35 wt %, even more preferably at least 40 wt %, and if achievable, at least 55 wt % and up to 95 wt % filler, while still maintaining the balance of performance properties, such as flexibility, tensile strength, impact strength, extensibility, elongation, heat resistance, low temperature flexibility, thermoformability and thermostability during processing, and excellent dispersion performance of fillers incorporated therein, necessary to effectively fabricate the filled polymer compositions into fabricated articles.
What is desired is a polymer composition that is capable of incorporating large quantities of filler with good dispersion of fillers incorporated while simultaneously exhibiting an enhanced balance of physical and mechanical properties for the applications of interest.